Insight into the Anchoring and Catalytic Effects of VO 2 and VS 2 Nanosheets as Sulfur Cathode Hosts for Li–S Batteries

Transition metal oxides and sulfides have been intensively investigated as host materials for the S cathode in lithium–sulfur (Li–S) batteries; however, the distinctions between them in battery operation have remained unclear. In this study, VO 2 and VS 2 nanosheets were systematically studied as host materials for Li–S batteries through theoretical calculations and experimental testing. First‐principles calculations demonstrated that VS 2 showed more favorable properties, including the inherent semi‐metallic conductivity of VS 2 , moderate adsorption strength for Li 2 S n , fast Li + transport with a low diffusion barrier, and accelerated surface redox reactions with a low Li 2 S decomposition barrier. In comparison, the low electronic conductivity and strong adsorption strength of VO 2 increased Li + diffusion as well as Li 2 S decomposition barriers of the electrode, resulting in relatively poor rate capability and cycle stability. In experiments, the VS 2 @S electrode exhibited superior electrochemical performance compared with VO 2 @S, giving a large capacity of 713 mAh g −1 at 5 C and a low capacity fading rate of 0.13 % per cycle over 200 cycles at 1 C. The constructed relationships between S cathode and host materials could guide the future design of high‐performance S cathodes for Li–S batteries.